The present disclosure relates to fluids, additives, and methods for use in subterranean operations, and more specifically, to improved methods and additives for eliminating or reducing concentrations of hydrogen sulfide or soluble sulfide ions for use in subterranean formations and fluids.
Hydrocarbon producing wells may contain many different formation sulfide, water, and other compounds. In order to evaluate the commercial value of a hydrocarbon producing well, or as an aid in operations and well planning, it is often useful to obtain information by analyzing the component concentrations of the produced fluid from a formation or an individual well. Numerous systems have been developed to evaluate a downhole fluid composition and the relative component concentrations in the downhole fluid.
Hydrogen sulfide (H2S) is a very toxic, flammable, and pungent gas that causes numerous problems in various aspects of the oil and gas industry. H2S is extremely corrosive to metal, which may damage or destroy tubing, casings, or other types of well bore equipment. H2S also presents health risks to operations personnel that may be exposed to H2S gas at a well site or in processing of well bore fluids. Severe iron sulfide scaling may also choke production, either in the production piping, perforations or within the producing formation itself. Thus, it is typically desirable to reduce or eliminate sulfides from subterranean formations and well bores, among other reasons, to control corrosion rates and to plan for safe development and production of the hydrocarbons.
The release of H2S gas can sometimes be controlled by maintaining the pH of the fluid containing H2S above 10. However, in many cases, it is not practical or possible to maintain this level pH in a fluid for extended periods of time. Sulfide scavengers are often used to react with H2S and convert it to a more inert form. Conventional H2S scavengers include certain aldehydes, certain amine-based chemicals, triazines, copper compounds, hydrogen peroxide, zinc compounds, and iron compounds. However, the reaction products of many of these compounds with H2S are poorly soluble in treatment fluids and/or fluids in the well bore, or may decompose, thereby releasing H2S. Moreover, many conventional sulfide scavengers themselves may have undesirable environmental and/or toxicity problems, and as such may be impractical to use or prohibited altogether in certain circumstances and/or jurisdictions.